Any of certain marine fish (family Megalopidae) having an elongated last dorsal fin ray and a bony throat plate between the sides of the protruding lower jaw. The scales are large, thick, and silvery. The Atlantic tarpon (Tarpon atlanticus or Megalops atlanticus) is found inshore in warm parts of the Atlantic Ocean, on the Pacific Ocean side of Central America, and sometimes in rivers. It habitually breaks the water's surface and gulps air. It grows to 6 ft (1.8 m) and 100 lb (45 kg) or larger and is a favourite game fish. The Pacific tarpon (M. cyprinoides) is similar